Pullulan mediated zinc oxide microparticles: Effect of synthesis temperature

Abstract

Zinc oxide (ZnO) has been gaining a lot of attention compared to the other semiconductor metal oxide. This is due to their favourable properties such as chemical stability, high electrochemical coupling coefficient, broad range of absorption radiation and high photostability. It also has wide band gap energy (3.37 eV), large exciton-binding energy (60 meV) and high thermal and mechanical stability at room temperature. Besides these desirable properties, the synthesis of ZnO has been widely studied as it is easy to synthesized and its properties such as band gap, shape and size can be controlled through synthesis parameters and methods. In this study, zinc oxide microparticles (ZnO-MCs) is produced with pullulan as mediator via precipitation method. The effect of synthesis temperature on the properties of synthesized ZnO-MCs were also studied. Based on the result obtained, all synthesized ZnO-MCs exhibited hexagonal wurtzite structure. As the synthesis temperature increases, the particles morphology changes from large spherical shape to flower-like morphology. Furthermore, the particle size also decreases with increasing temperature. This result is supported by surface area and pore analysis where the surface area ranging from 6.22 to 22.78 m2 g-1 was obtained as the synthesis temperature increases. All these results indicate that synthesis method and parameters will affect the properties of synthesized ZnO-MCs.